Toolarmy mentions that the next batch of Lateralus Signed Vinyl will be available at 1pm January 28th PST.  For all you Australians this translates to 8am on Sunday the 29th, Eastern Standard Daylight Savings time.  To work out when it will be available in your part of the world, use this site:

http://www.timeanddate.com/worldclock/converter.html